This paper investigates the char forming effect of para-aramid fiber and the flame-retardant efficiency of para-aramid fiber synergizing with ammonium polyphosphate on polypropylene/ethylene propylene diene monomer. Para-aramid fiber was firstly modified by phosphoric acid, and then modified by 3-aminopropyltriethoxy. Para-aramid fiber and modified para-aramid fiber were characterized by field-emission scanning electron microscope, energy-dispersive analysis and Fourier transform infrared spectroscopy. Fourier transform infrared spectroscopy illustrated that P–O groups and Si–O groups appeared on the surface of modified para-aramid fiber. The intumescent flame retardants containing para-aramid fiber/ammonium polyphosphate or modified para-aramid fiber/ammonium polyphosphate was introduced into polypropylene/ethylene propylene diene monomer. The flame-retardant efficiency of polypropylene/ethylene propylene diene monomer composites were investigated by limiting oxygen index, UL-94 vertical burning and cone calorimeter test. The polypropylene/ethylene propylene diene monomer composite containing 34.5 wt% ammonium polyphosphate and 0.5 wt% modified para-aramid fiber achieved a UL-94 V0 rating with a limiting oxygen index of 28, as well as showed a 23.6% reduction of total heat release and a 47.0% reduction of total smoke release. The thermal stability of polypropylene/ethylene propylene diene monomer composites were investigated by thermogravimetric analysis. The residual char layers of polypropylene/ethylene propylene diene monomer composites were analyzed by field-emission scanning electron microscope. The tensile and tear strength of polypropylene/ethylene propylene diene monomer composites were also tested. After 1 phr modified para-aramid fiber was added, the tensile strength and tear strength increased by 33.3% and 35.9%, respectively. The results indicated that modified para-aramid fiber/ammonium polyphosphate/polypropylene/ethylene propylene diene monomer had better flame-retardant efficiency, thermal stability, smoke suppression and mechanical properties with the synergistic effect of P, N, Si elements.

本文研究了对位芳纶纤维的成炭效果以及对位芳纶纤维与多磷酸铵协同作用对聚丙烯/乙烯丙烯二烯单体的阻燃效果。对位芳族聚酰胺纤维先用磷酸改性，然后再用3-氨丙基三乙氧基改性。通过场发射扫描电子显微镜，能量色散分析和傅里叶变换红外光谱对对位芳纶纤维和改性对位芳纶纤维进行了表征。傅里叶变换红外光谱表明，在改性对位芳族聚酰胺纤维的表面上出现了PO基团和SiO基团。将包含对位芳族聚酰胺纤维/聚磷酸铵或改性的对位芳族聚酰胺纤维/聚磷酸铵的膨胀型阻燃剂引入聚丙烯/乙烯丙烯二烯单体中。通过极限氧指数，UL-94垂直燃烧和锥形量热仪试验研究了聚丙烯/乙烯丙烯二烯单体复合材料的阻燃效率。包含34.5 wt％的聚磷酸铵和0.5 wt％的改性对位芳族聚酰胺纤维的聚丙烯/乙烯丙烯二烯单体复合材料达到UL-94 V0等级，极限氧指数为28，并且总热量释放减少了23.6％并减少了47.0％的总烟雾释放量。通过热重分析研究了聚丙烯/乙烯丙烯二烯单体复合材料的热稳定性。通过场发射扫描电子显微镜分析了聚丙烯/乙烯丙烯二烯单体复合材料的残余炭层。还测试了聚丙烯/乙烯丙烯二烯单体复合材料的拉伸强度和撕裂强度。加入1 phr改性对位芳族聚酰胺纤维后，抗张强度和撕裂强度分别提高了33.3％和35.9％。结果表明，改性对位芳纶纤维/聚磷酸铵/聚丙烯/乙烯丙烯二烯单体具有较好的阻燃效率，热稳定性，抑烟性和力学性能，并具有P，N，Si元素的协同​​作用。